TWI647503B - Titanium copper foil with plating layer, electronic component, joint body, method for connecting titanium copper foil and conductive member, autofocus module, autofocus camera module, and method for manufacturing titanium copper foil - Google Patents

Abstract

The present invention provides a titanium copper foil which is excellent in adhesion to solder, has high discoloration resistance with respect to a high-temperature and high-humidity environment, an acid liquid or an alkali liquid, and is excellent in etching workability. A titanium copper foil whose base material has a composition of 1.5 to 5.0% by mass of Ti, the balance being composed of copper and unavoidable impurities, and a base material having a thickness of 0.018 to 0.1 mm, having a Sn plating layer on the surface of the base material, according to The bond strength in the solder bond strength test defined in the specification is 0.5 N or more.

Description

Titanium copper foil with plating, electronic component, bonded body, method for connecting titanium copper foil and conductive member, autofocusing module, autofocus camera module, and method for manufacturing titanium copper foil

The present invention relates to a titanium copper foil having a plating layer. In particular, the present invention relates to a titanium copper foil suitable for use as a conductive spring material for an autofocus camera module (AFM).

The camera lens portion of the mobile phone uses an electronic component called an autofocus camera module (AFM). In terms of the autofocus function of the camera of the mobile phone, on the one hand, the lens is moved in a certain direction by the elastic force of the material used in the AFM, and the electromagnetic force generated by the current flowing through the coil wound around the other side is made. The lens moves in a direction opposite to the direction in which the material acts. The camera lens is driven by a mechanism similar to the above and functions as an autofocus function (e.g., Patent Documents 1, 2).

Therefore, the copper alloy foil used in the AFM needs to be able to withstand the degree of deformation of the material due to electromagnetic force. If the strength is low, the material cannot withstand the displacement caused by the electromagnetic force, and permanent deformation (relaxation) occurs. Once slack occurs, the lens cannot move to the desired position when a certain current flows, and the auto focus function cannot be performed.

At present, a spring material for AFM is a Cu-Ni-Sn-based copper alloy foil having a foil thickness of 0.1 mm or less and a tensile strength of 1100 MPa or more. However, with the demand for cost reduction in recent years, there has been an increase in the demand for titanium copper foil which is relatively inexpensive compared to Cu-Ni-Sn-based copper alloy foil.

Under the above background, it has been proposed many times that titanium copper is used as a spring material for AFM. As disclosed in Patent Document 3, a titanium copper foil is proposed which has a 0.2% lodging strength and a fatigue resistance of a titanium copper foil, and contains 1.5 to 5.0% by mass of Ti, and the balance is composed of copper and unavoidable impurities. The 0.2% relief strength in the direction parallel to the rolling direction is 1100 MPa or more, and, in the rolled surface, the integrated intensity I ₍₂₂₀₎ and ( ₂₂₀₎ of the (220) crystal plane measured using X-ray diffraction 311) The integrated intensity I ₍ 311) of the crystal plane satisfies the relationship of I ₍₂₂₀₎ / I ₍₃₁₁₎ ≧ 15. Further, Patent Document 4 proposes a titanium copper foil which contains 1.5 to 5.0% by mass of Ti for the purpose of improving fatigue resistance, and the balance is composed of copper and unavoidable impurities in a direction parallel to the rolling direction. The upper 0.2% relief strength is 1100 MPa or more, and the arithmetic mean roughness (Ra) in the direction perpendicular to the rolling direction is 0.1 μm or less.

[Practical Technical Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-280031.

Patent Document 2: Japanese Patent Laid-Open Publication No. 2009-115895.

Patent Document 3: Japanese Patent Laid-Open Publication No. 2014-80670.

Patent Document 4: Japanese Patent Laid-Open Publication No. 2014-37613.

On the other hand, in the process of manufacturing a spring material for AFM from a titanium copper foil, a method of shape-processing a titanium copper foil by etching is generally employed. Further, according to the use of the spring material composed of the titanium copper foil, in addition to the plating process for the purpose of preventing discoloration, there are cases where welding, adhesion to a resin, and sealing with a resin are also possible. The AFM uses the resulting spring material to engage the coil through the solder. However, the main purpose of the development of the conventional titanium copper foil for AFM is to improve strength or fatigue resistance, and it is considered insufficient in carrying out the above-described etching processing, plating processing, and bonding with solder.

In the etching process, the basic performance required for the titanium copper foil is that it has excellent etching workability in order to accurately form the desired shape.

Further, in the etching processing or the plating processing, a step of treating the material to be processed in an acid liquid or an alkali liquid is included. The plating process further includes a process of performing treatment in the plating solution. In the step of using the various treatment liquids as described above, water is washed and dried to remove the treatment liquid. For thicker products of the expanded copper products of the sheets and strips, it is easy to wash and dry the treatment liquid, and it can be removed by a roll type or a blow type. On the other hand, if the shape of the member is fine and the thickness is small, it is extremely difficult to remove the moisture contained in the treatment liquid or the water wash water. When moisture remains, the remaining treatment liquid component in the moisture inevitably reacts with the material to be treated to form a compound, and the water evaporates and adheres to the surface as a residue. Especially in the case of titanium copper, due to the presence of Ti as an active element, The physicochemical components react and produce complex compounds, which are prone to residue. When there is a residue, it is easy to cause discoloration after etching the shape of a member or the like (it is judged to be abnormal in the visual inspection of the product when the discoloration occurs, and the yield ratio is lowered), and is bonded to a member such as solder or resin. At the time, the problem of a decrease in joint strength is likely to occur.

In the etching process using photolithography, a resist film having a shape corresponding to the shape of the member is formed on the surface of the material to be etched. The resist film must be bonded to the material to be etched with a predetermined strength, and if the strength is insufficient, it is peeled off during etching. Further, when the resist film is peeled off during etching, etching cannot be performed uniformly, and it is difficult to obtain a target size and shape. Therefore, in order to improve the bonding strength, the entire surface treatment may be performed before etching. The whole surface treatment refers to a treatment of roughening the surface by acid etching the surface layer, and has an effect of improving the bonding strength of the resist film. Further, in the plating treatment, surface contaminants are removed and the oxide film exposes a new surface. Therefore, in the pre-plating treatment, the surface layer may be corroded by acid. However, if such a full surface treatment or a pre-plating treatment is directly performed on the surface of the titanium copper, surface residue is generated after the etching process, and the bonding strength with the member may be lowered. Further, in the joining of welding, adhesion to a resin, and sealing with other members such as resin sealing, good bonding strength is also sought.

In view of the above, an object of the present invention is to provide a titanium copper foil which is excellent in adhesion to solder, has good discoloration resistance with respect to a high-temperature and high-humidity environment, an acid liquid or an alkali liquid, and is excellent in etching workability.

The inventors originally proposed to protect the surface of titanium copper by plating the surface of titanium copper with an element Ni which is difficult to oxidize. Thereby, it can be determined that the surface oxidation energy is controlled, and the resistance to the acid liquid or the alkali liquid can be improved, but on the other hand, the etching workability is deteriorated, and the optimum effect of the AFM spring material cannot be exhibited. Therefore, the inventors of the present invention have further discussed the following matters: while controlling the glossiness of the surface of the base material, a Sn plating layer is formed on the surface of the titanium copper foil to improve the resistance against the acid liquid or the alkali liquid, and at the same time, it is ensured. Etching processability.

The present invention is based on the above knowledge. In one embodiment, in the case of a titanium copper foil, the composition of the base material is 1.5 to 5.0% by mass of Ti, and the balance is composed of copper and unavoidable impurities. The thickness is 0.018 to 0.1 mm, and there is a Sn plating layer on the surface of the base material. The bonding strength of the titanium copper foil as defined in the specification in the solder bond strength test is 0.5 N or more.

In an embodiment of the titanium copper foil according to the present invention, the thickness of the Sn plating layer is 0.01 to 2.0 μm.

In another embodiment of the titanium copper foil according to the present invention, the base material further contains a total amount of 0 to 1.0% by mass selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, and Cr. And more than one element in Zr.

In still another embodiment of the titanium copper foil according to the present invention, the tensile strength in a direction parallel to the rolling direction is 1100 MPa or more.

In still another embodiment of the titanium copper foil according to the present invention, the bonding strength is 20 N or more.

In still another embodiment of the titanium copper foil according to the present invention, the reduction ratio of the bonding strength after heating at a temperature of 85 ° C for 100 hours with respect to the bonding strength before heating is less than 5%.

In still another embodiment of the titanium copper foil according to the present invention, the titanium copper foil is used for etching processing.

In another embodiment, the invention is an electronic component comprising the titanium copper foil according to the invention.

In still another embodiment, the present invention relates to a bonded body of a titanium copper foil and a solder according to the present invention, which has a joint portion joined to a solder on a surface of a plating layer of the titanium copper foil.

In still another embodiment, the present invention provides a method for joining a titanium copper foil and a conductive member, comprising the steps of: shape-treating the titanium-copper foil according to the present invention by etching; and shaping the shape of the obtained titanium copper foil The processed product is a step of joining the conductive member to the portion having the plating layer by soldering.

In still another embodiment, the present invention is an autofocus module including the titanium copper foil according to the present invention as a spring material.

In still another embodiment, the present invention is an autofocus camera module having a lens; a spring member that elastically applies the titanium copper foil according to the present invention to the initial position in the optical axis direction; and generates An electromagnetic driving mechanism that is capable of driving the lens in the optical axis direction against an electromagnetic force of the urging force of the spring member, and the electromagnetic driving mechanism includes a coil that is joined to the coil by welding at a portion having the plating layer.

In still another embodiment, the present invention is a method for producing a titanium copper foil, the method comprising: a step of preparing a base material having a composition of 1.5 to 5.0% by mass of Ti, the balance being copper and inevitable impurities The composition has a thickness of 0.018 to 0.1 mm, a surface gloss of 100 to 200, and a step of forming a Sn plating layer having a thickness of 0.01 μm or more on the surface of the base material.

In another embodiment of the method for producing a titanium copper foil according to the present invention, the thickness of the Sn plating layer is 0.01 to 2.0 μm.

In still another embodiment of the method for producing a titanium copper foil according to the present invention, the base material further contains a total amount of 0 to 1.0% by mass selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, and P. One or more elements of Si, Cr, and Zr.

In still another embodiment of the method for producing a titanium copper foil according to the present invention, the arithmetic mean roughness Ra of the surface of the base material having a surface gloss of 100 to 200 is 0.5 μm or less.

The titanium-clad foil having a plating layer according to the present invention is less likely to cause surface residue after etching or plating. Thereby, discoloration of the titanium copper foil can be prevented, and the bonding strength with the component can be controlled to be lowered. Further, the copper foil having a plating layer according to the present invention has such characteristics as to suppress surface residue after etching or plating, and also has excellent etching workability. Therefore, the titanium-clad foil having a plating layer according to the present invention is very suitable for use as a spring member for AFM which is required to have strength, discoloration resistance, etching property and weldability.

1‧‧‧Automatic Focusing Camera Module

2‧‧‧Y yoke

2a‧‧‧ inner wall

2b‧‧‧ outer wall

3‧‧‧ lens

4‧‧‧ magnet

5‧‧‧ bracket

6‧‧‧ coil

7‧‧‧Base

8‧‧‧Frame

9a‧‧‧ (upper side) spring parts

9b‧‧‧ (lower) spring parts

10a‧‧‧ cover

10b‧‧‧ cover

Fig. 1 is a cross-sectional view showing an autofocus camera module according to the present invention.

Fig. 2 is an exploded perspective view of the autofocus camera module of Fig. 1.

Fig. 3 is a cross-sectional view showing the operation of the autofocus camera module of Fig. 1.

Fig. 4 is a view showing an example of measurement results in a solder bond strength test.

(1) Ti concentration

In the titanium-clad foil having a plating layer according to the present invention, titanium copper is used as a base material, and the composition of the titanium copper is 1.5 to 5.0% by mass of Ti, and the balance is composed of copper and unavoidable impurities. So-called The impurities that can be avoided are: substances which are present in the raw material of the metal product or which are inevitably mixed in the manufacturing process, which are not originally required, but since it is a trace amount, it does not affect the characteristics of the metal product, so Impurities allowed. Further, the total amount of unavoidable impurities is generally 50 ppm by mass or less, typically 30 ppm by mass or less, more typically 10 ppm by mass or less. Titanium copper is solid-dissolved into the Cu matrix by solution treatment, and the fine precipitates are dispersed in the alloy by aging treatment, whereby the strength and electrical conductivity can be increased. When the Ti concentration is less than 1.5% by mass, precipitation of precipitates is insufficient, and the desired strength cannot be obtained. When the Ti concentration exceeds 5.0% by mass, the workability is deteriorated, and the material is easily cracked during rolling. The Ti concentration is preferably 2.9 to 3.5% by mass in consideration of the balance between strength and workability.

(2) Other added elements

Further, the base material contains one or more elements selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr in a total amount of 0 to 1.0% by mass, thereby enabling further Increase the strength. The total content of these elements is 0, which means that the above elements may not be included. The reason why the upper limit of the total content of the above elements is 1.0% by mass is that when it exceeds 1.0% by mass, the workability is deteriorated, and the material is easily cracked during rolling. In consideration of the balance between strength and workability, one or more of the above elements may be contained in a total amount of 0.005 to 0.5% by mass.

Further, Ag is preferably added in an amount of 0.5% by mass or less, and more preferably in an amount of 0.1% by mass or less. The amount of addition of B is preferably 0.5% by mass or less, and more preferably 0.05% by mass or less. The amount of addition of Co is preferably 0.5% by mass or less, and more preferably 0.1% by mass or less. The Fe is preferably added in an amount of 0.5% by mass or less, and more preferably in an amount of 0.25 % by mass or less. The amount of Mg added is preferably 0.5% by mass or less, and more preferably 0.1% by mass or less. The amount of addition of Mn is preferably 0.1% by mass or less, and more preferably 0.05% by mass or less. The amount of addition of Mo is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. The amount of Ni added is preferably 0.5% by mass or less, and more preferably 0.1% by mass or less. P is preferably added in an amount of 0.1% by mass or less, and more preferably 0.05% by mass or less. The Si is preferably added in an amount of 0.1% by mass or less, and more preferably in an amount of 0.05% by mass or less. The amount of Cr added is preferably 0.5% by mass or less, and more preferably 0.4% by mass or less. A preferred addition amount of Zr is 0.5% by mass or less, and a more preferable addition amount is 0.1% by mass or less. However, it is not limited to the above addition amount.

(3) Tensile strength

The titanium copper which is a conductive spring material of the autofocus camera module preferably has a tensile strength of 1100 MPa or more. In the titanium copper according to the present invention, the tensile strength in a direction parallel to the rolling direction can be It reaches 1100MPa or more. The tensile strength of titanium copper according to the present invention is 1200 MPa or more in a preferred embodiment, and 1300 MPa or more in a more preferred embodiment.

The upper limit of the tensile strength is not particularly limited in view of the strength as the object of the present invention, but the tensile strength of the titanium copper according to the present invention is generally 2000 MPa or less, typically due to time and money. It is 1600 MPa or less.

In the present invention, the tensile strength in a direction parallel to the rolling direction of titanium copper is measured in accordance with JIS Z2241-2011 (Metal Material Tensile Test Method).

(4) Form of titanium copper

The base material of the coated titanium-copper according to the present invention is a foil having a thickness of 0.018 to 0.1 mm. Since the thickness of the base material is 0.018 mm or more, the strength necessary as a spring material can be secured. The thickness of the base material is preferably 0.03 mm or more. In addition, when the thickness of the base material is 0.1 mm or less, it is advantageous to reduce the size of the electronic component when forming an electronic component such as a spring material using a titanium copper foil. The thickness of the base material is preferably 0.08 mm or less, more preferably 0.06 mm or less.

(5) plating

One of the characteristics of the coated titanium copper according to the present invention is that the surface of the base material has a Sn plating layer. Although it is not intended to limit the present invention by theory, it has a Sn plating layer, whereby the resistance to an acid liquid or an alkali liquid is improved, and it is difficult to generate a residue on the surface after etching or plating. Thereby, discoloration of the titanium copper foil can be prevented, and a decrease in the bonding strength with a member such as solder or resin can be suppressed. Further, since the Sn plating layer is excellent in etching workability, it is possible to ensure high dimensional accuracy when manufacturing a fine electronic component such as a spring material. The Sn plating layer can also be set as a reflowed Sn plating layer.

A plating layer may be formed on a part or all of the surface of the foil as a base material. Further, a plating layer may be formed on one surface or both surfaces of the main surface of the foil as the base material. The plating can be obtained by wet plating such as electroplating, electroless plating, and immersion plating. From the viewpoint of cost, electroplating is preferred.

For the plating layer, the solder bonding strength at the time of performing the solder bonding strength test described later is preferably 0.5 N or more, more preferably 1 N or more, further preferably 2 N or more. With solder bonding The titanium-copper foil of the plating layer having a strength of less than 0.5 N is chemically defective, and it is easy to cause problems in etching, plating, resin bonding, and resin sealing. That is, discoloration occurs when various surface treatments are performed, or defects occur when other members are bonded to the titanium copper foil.

The titanium-clad foil having a plating layer according to the present invention can be processed into a desired shape after forming a Sn plating layer. For example, when a titanium-clad foil having a plating layer according to the present invention is used as a spring material for an auto-focusing module, a circuit portion or a spring portion is formed by etching and the titanium-copper foil is processed into a desired shape. The shape processing by etching can be carried out by a known method. For example, a method can be employed in which the surface of the base material which is desired to be retained after etching is protected by an etching resistant protective film, followed by dry etching or wet etching and shape. After processing, the protective film is removed.

The thickness of the Sn plating layer is preferably from 0.01 to 2.0 μm from the viewpoint of the effect desired by the present invention. The thickness of the Sn plating layer is large from the viewpoint of attaching importance to the bonding strength of the solder, and specifically, it is preferably 0.1 to 2.0 μm, more preferably 1.0 to 2.0 μm. On the other hand, when the thickness of the Sn plating layer is increased, the economy (cost) is poor. Further, according to the plating structure according to the present invention, even if the thickness of the plating is reduced, the bonding strength with the solder can be improved to a high level of practicality. Therefore, from the viewpoint of paying attention to the cost of plating, the thickness of the Sn plating layer is preferably 0.01 to 1.0 μm, more preferably 0.01 to 0.1 μm. Further, from the viewpoint of balancing the bonding strength with the solder and the plating cost, the thickness of the Sn plating layer is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.5 μm. In addition, the operator can select an arbitrary plating thickness from the viewpoints of cost, yield, and the like.

In the present invention, the thickness of the plating layer is measured in accordance with the fluorescent X-ray type test method of JIS H8501-1999. In the examples, measurement was performed using a fluorescent X-ray film thickness meter (SFT9250) manufactured by Hitachi High-Technologies Co., Ltd.

(6) Solder adhesion

The coated titanium copper foil according to the present invention can have excellent solder adhesion. In a preferred embodiment, the titanium-copper foil having a plating layer according to the present invention can achieve an average bond strength of 0.5 N or more, preferably 0.8 N or more, in a solder bond strength test described below. 1.0 N or more, more preferably 1.2 N or more, for example, it can be set to 0.5 to 1.5 N or more.

Further, the copper foil having a plating layer according to the present invention has excellent heat resistance, and in one embodiment, the solder bond strength after heating at 85 ° C for 100 hours is reduced by less than 5%.

The procedure of the solder bond strength test will be described. The lead-coated solder (Sn-3.0% by mass Ag-0.5% by mass Cu) is bonded to a titanium-clad foil having a plating layer and a pure copper foil (alloy No. C1100 specified in JIS H3100-2012, foil thickness 0.02 mm to 0.05 mm). . The titanium copper foil is a rectangle having a width of 15 mm and a length of 200 mm, and the pure copper foil is a rectangle having a width of 20 mm and a length of 200 mm, and a lead-free solder (diameter: 0.4 ± 0.02 mm, length: 120 ± 1 mm) for an area of 30 mm × 15 mm in the center portion in the longitudinal direction. Within the above-mentioned area, the bonding was carried out at 245 ° C ± 5 ° C as the bonding temperature. After the bonding, the bonding strength was measured by performing a 180° peeling test at a speed of 100 mm/min. The average value of the load (N) in the 40 mm section from 30 mm to 70 mm of the peeling displacement was taken as the bonding strength. Fig. 4 shows an example of measurement results in the solder bond strength test.

(7) Use

The titanium-copper foil with plating is not limited, but is suitable as a switch, a connector (especially a fork-type FPC connector that does not require excessive bending workability), an auto-focusing camera module, a socket, a terminal, a relay The use of materials such as electronic components. Further, the titanium-clad foil having a plating layer and the insulating substrate according to the present invention are adhered to form a copper-clad laminate so as to expose the plating layer, and the wiring is formed as a printed wiring board by an etching process, and the metal wiring of the printed wiring board is welded. It is equipped with various electronic components to manufacture printed circuit boards.

In summary, the coated titanium copper according to the present invention is suitable for use as a spring material for an auto-focusing module. Therefore, in one embodiment, the present invention is an autofocus module having the titanium copper according to the present invention as a spring material. A typical auto-focusing module includes a lens and a spring member made of a coated titanium-copper according to the present invention, and a force acting against the spring member, which is elastically biased to an initial position in the optical axis direction of the present invention. The electromagnetic force thus enables the lens to be driven to the electromagnetic drive mechanism in the direction of the optical axis. The electromagnetic drive mechanism is exemplarily provided with " A cylindrical yoke having a zigzag shape, a coil housed inside the inner peripheral wall of the yoke, and a magnet surrounding the coil and housed inside the outer peripheral wall of the yoke. The spring member is joined to the coil (typically a wire of a coil) by soldering where the coating is present.

1 is a cross-sectional view showing an example of an autofocus camera module according to the present invention, FIG. 2 is an exploded perspective view showing the autofocus camera module of FIG. 1, and FIG. 3 is an autofocus camera showing Fig. 1. A cross-sectional view of the action of the module.

The auto focus camera module 1 has: " a yoke 2 having a cylindrical shape; a magnet 4 attached to the outer wall of the yoke 2; a bracket 5 having a lens 3 at a central position; a coil 6 mounted in the bracket 5; and a base 7 to which the yoke 2 is mounted a frame 8 supporting the base 7, two spring members 9a, 9b supporting the bracket 5 from above and below, and two cover bodies 10a, 10b covering the upper and lower sides. The two spring members 9a and 9b are the same member, and the bracket 5 is vertically clamped and supported in the same positional relationship, and functions as a power supply path of the coil 6. The carriage 5 is moved upward by applying a current to the coil 6. In the present specification, the descriptions of "upper" and "lower" are used as appropriate, and the meaning of "upper" and "upper" in the first drawing means the positional relationship from the camera lens toward the subject.

The yoke 2 is a magnetic body such as soft iron, and is formed to be closed on the upper surface portion. The cylindrical shape of the zigzag has a cylindrical inner wall 2a and an outer wall 2b. " An annular magnet 4 is attached (bonded) to the inner surface of the outer wall 2b of the zigzag shape.

The bracket 5 is a molded product formed of a synthetic resin having a cylindrical structure having a bottom surface portion, and supports the lens at a center position, and the pre-formed coil 6 is attached to the outside of the bottom surface. The yoke 2 is fitted and assembled to the inner peripheral portion of the susceptor 7 of the rectangular resin molded article, and the yoke 2 is entirely fixed by the frame 8 of the resin molded article.

The outermost peripheral portions of the arbitrary spring members 9a and 9b are respectively sandwiched and fixed by the frame 8 and the susceptor 7, and the inner peripheral portion is fitted to the bracket 5 every 120°, and fixed by heat caulking or the like.

The spring member 9b and the base 7 and the spring member 9a and the frame 8 are fixed by adhesion or heat riveting, and the cover 10b is attached to the bottom surface of the base 7, and the cover 10a is attached to the upper portion of the frame 8. The spring member 9b is sandwiched and fixed between the base 7 and the lid body 10b, and the spring member 9a is sandwiched and fixed between the frame 8 and the lid body 10a.

One side wire of the coil 6 extends upward through a groove provided in the inner circumferential surface of the bracket 5, and is welded to the spring member 9a. The other side wire extends downward through a groove provided in the bottom surface of the bracket 5, and is welded to the spring member 9b.

The spring members 9a and 9b are leaf springs of the titanium copper foil according to the present invention. It has elasticity to elastically apply the lens 3 to the initial position in the optical axis direction. At the same time, it acts as a path for supplying power to the coil 6. One of the outer peripheral portions of the spring members 9a and 9b protrudes outward and functions as a power supply terminal.

The cylindrical magnet 4 is magnetized in a radial direction to form " The inner wall 2a, the upper surface portion, and the outer wall 2b of the word-shaped yoke 2 are magnetic paths of the path, and the coil 6 is disposed in a gap between the magnet 4 and the inner wall 2a.

The spring members 9a and 9b have the same shape, and are attached in the same positional relationship as shown in Figs. 1 and 2, so that the axial misalignment when the bracket 5 is moved upward can be suppressed. Since the coil 6 is formed by press-molding after winding, the accuracy of the outer diameter of the finished product is improved, and it can be easily placed in a predetermined narrow gap. The lowermost position of the bracket 5 is placed on the base 7, and the uppermost position is placed against the yoke 2, so that an overhead mechanism is provided in the up and down direction to prevent falling off.

Fig. 3 is a cross-sectional view showing a state in which a current is applied to the coil 6 to move the carriage 5 having the lens 3 for automatic focusing upward. When a power source is applied to the power supply terminals of the spring members 9a, 9b, a current flows through the coil 6 to apply an upward electromagnetic force to the bracket 5. On the other hand, in the bracket 5, the restoring force of the two connected spring members 9a and 9b acts downward on the bracket 5. Therefore, the distance by which the carriage 5 moves upward is a position where the electromagnetic force and the restoring force are balanced. Thereby, the amount of movement of the carriage 5 can be determined by the amount of current applied to the coil 6.

The upper spring member 9a supports the upper surface of the bracket 5, and the lower spring member 9b supports the lower surface of the bracket 5. Therefore, the restoring force acts equally on the upper surface and the lower surface of the bracket 5, and the lens 3 can be attached. The axis misalignment is suppressed to a small extent.

Therefore, when the carriage 5 is moved upward, guidance of a rib or the like is not required or used, and since there is no sliding friction due to the guidance, the amount of movement of the bracket 5 is purely electromagnetic force and restoring force. Balanced by the balance, the lens 3 is smooth and accurate. This enables automatic focusing with small lens misalignment.

Further, although the cylindrical magnet 4 has been described, the present invention is not limited thereto, and may be divided into three to four equal portions for radial magnetization, and adhered to the inner surface of the outer wall 2b of the yoke 2 and fixed.

(8) Manufacturing method

An example of a method for producing a base material of titanium copper according to the present invention will be described. First, an ingot is produced by melting and casting. Preferably, the melting and casting prevent oxidative attrition of titanium and are therefore carried out substantially in a vacuum or inert gas atmosphere. If there is a melting residue of the added element in the melting, High strength does not play an effective role. Because, in order to remove the melting residue, it is sufficiently stirred after the addition of the third element having a high melting point such as Fe or Cr, and on the basis of this, it is kept for a certain period of time. On the other hand, since Ti is relatively easily melted in Cu, it is sufficient to melt the third element and then add it. Therefore, it is preferable to add an element of one or more of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr to Cu, and then add a predetermined amount of Ti to produce an ingot.

Thereafter, hot rolling, cold rolling I, solution treatment, cold rolling II, and aging treatment are sequentially performed, whereby a copper alloy having a desired thickness and characteristics can be obtained. In order to achieve high strength, cold rolling III can be performed after the aging treatment. The conditions of hot rolling and subsequent cold rolling I are as long as they are carried out in accordance with the conventional conditions carried out in the production of titanium copper, and there are no particularly required conditions. Further, the solution treatment may be carried out under customary conditions, for example, at 700 to 1000 ° C for 5 seconds to 30 minutes.

In order to obtain high strength, the reduction ratio of cold rolling II is preferably 55% or more. More preferably, it is 60% or more, and further preferably 65% or more. The upper limit of the reduction ratio is not particularly limited in view of the strength as the object of the present invention, but it is industrially not more than 99.8%.

Preferably, the aging treatment has a heating temperature of 200 to 450 ° C and a heating time of 2 to 20 hours. If the heating temperature is less than 200 ° C or exceeds 450 ° C, it is difficult to obtain high strength. It is also difficult to obtain high strength when the heating time is less than 2 hours or more than 20 hours.

The reduction ratio at the time of performing cold rolling III is preferably 35% or more. More preferably, it is 40% or more, and further preferably 45% or more. When the reduction ratio is less than 35%, it is difficult to obtain high strength. The upper limit of the reduction ratio has no special regulations in terms of strength, but it does not exceed 99.8% in industry.

Further, it should be understood that those skilled in the art can appropriately perform processes such as polishing, polishing, shot blasting, and the like for removing surface scale during the interval of the above-described respective steps.

In the cold rolling step of the thickness finishing of the product (the cold rolling II corresponds to the step, and the cold rolling III corresponds to the step when the cold rolling III is performed), the fine unevenness of the surface is adjusted in the subsequent plating step to cause plating. The bond strength reaches 0.5N or more. If the surface has a small unevenness, the plating adhesion strength is increased by finding the fixing effect or increasing the adhesion area. That is, in the cold rolling, fine unevenness is imparted to the surface by appropriately generating the oil groove, thereby obtaining high plating adhesion strength. The minute irregularities on the surface are so small that they cannot be expressed by the surface roughness Ra or the like, but can be expressed by glossiness. The invention relates to The glossiness is defined as the specular gloss when measured at an incident angle of 60 degrees in the rolling direction based on JIS Z8741-1997.

When the gloss is low, the minute irregularities are large, and when the gloss is high, the minute irregularities are small. In the embodiment described later, in order to achieve a solder bonding strength of 0.5 N or more in the soldering test, a titanium foil has a preferred gloss of 100 to 200, in terms of bonding strength with solder. In view, it is preferably 100 to 170, more preferably 100 to 130. In the cold rolling process of the thickness finishing of the product, the rolling table is designed to achieve a gloss of 100 to 200. The rolling table refers to the degree of processing in the primary rolling pass, the viscosity and temperature of the rolling oil, the rolling speed, the rolling tension, the material of the rolling roll, or the diameter of the rolling roll. In order to achieve a gloss of 100 to 200, for example, when the tensile strength of the titanium copper foil is 1200 MPa, the rolling speed in the final path of the cold rolling of the product thickness finishing is 50 m/min or more. When the rolling speed is high, the rolling oil is promoted to flow between the rolling rolls and the titanium copper foil, and the oil grooves are easily generated. When the rolling speed is less than 50 m/min, the rolling oil does not have a sufficient oil groove due to insufficient inflow. As a result, the glossiness exceeds 200, and the minute irregularities on the surface become small, so the plating adhesion strength is less than 2N. Further, even if the gloss is less than 100, the bonding strength is not adversely affected, but it is necessary to increase the rolling speed in order to obtain a gloss of less than 100. When the rolling speed is high, it is difficult to obtain a uniform shape by thermal expansion of the rolls, and it is easy to deteriorate the manufacturability. Therefore, it is preferable that the glossiness is set to 100 or more.

In addition, after the cold rolling step of performing the thickness finishing of the product, the arithmetic mean roughness Ra in the direction in which the rolling direction of the surface of the titanium-copper foil before the plating step is parallel is measured in accordance with JIS B0601-2001. If it is a thin material such as a titanium copper foil, when the surface roughness is large, a thick portion or a thin portion of the thickness is likely to be locally generated, and it is difficult to obtain the performance as a spring. Therefore, from the viewpoint of obtaining uniform elasticity, the Ra of the surface of the titanium copper foil is preferably adjusted to 0.5 μm or less, more preferably 0.1 μm or less, and for example, it can be set to 0.01 to 0.5 μm, typically 0.02 to 0.2. Mm.

[Examples]

The embodiments of the present invention are shown below, but they are intended to better understand the present invention and its advantages, and are not intended to limit the present invention.

The composition of the base material of each sample contained the predetermined alloy component described in Table 1-1, and the balance was composed of copper and unavoidable impurities. The electrolytic copper 2.5 KG was melted in a vacuum melting furnace, and alloying elements were added to obtain the alloy combination described in Table 1-1. Casting the molten metal in a mold made of cast iron An ingot having a thickness of 30 mm, a width of 60 mm, and a length of 120 mm was produced. After the ingot was subjected to hot rolling, the following steps were sequentially carried out to prepare a titanium copper foil having a foil thickness of 0.03 mm.

(1) Hot rolling: The ingot was heated at 950 ° C for 3 hours, and rolled until the thickness was 10 mm.

(2) Grinding: The scale produced by hot rolling was removed by a grinder. The thickness after grinding was 9 mm.

(3) Cold rolling I: In order to obtain the final foil thickness, the reduction ratio of the cold rolling II is considered and the reduction ratio is adjusted.

(4) Solution treatment: The material was placed in an electric furnace heated to 800 ° C, and after holding for 5 minutes, the sample was placed in a water tank for rapid cooling.

(5) Cold rolling II: rolling was performed at a reduction ratio of 98%. At this time, the rolling schedule in the final path of the cold rolling was adjusted to the speed described in Table 1-1, whereby the gloss was changed.

(6) Aging treatment: The material was heated to 300 ° C and heated in an Ar atmosphere for 2 hours.

After the surface of each obtained titanium copper foil was degreased and pickled and purified, the surface was plated by the type and thickness of plating described in Table 1-2.

The Sn plating layer was formed under the following plating conditions.

‧Sn ion: 29g/L

‧ bath temperature: 40 ° C

‧ Current density: 1.7A/dm ²

‧Time: Adjust according to plating thickness

Further, after the Sn plating was performed according to the test number, the reflow was performed. The reflux condition can be carried out by a generally used method, and is carried out in the present invention at 400 ° C for 100 seconds.

The Ni plating layer is formed by the following plating conditions.

‧Ni ion: 20g/L

‧PH:3.0

‧ bath temperature: 50 ° C

‧ Current density: 5.0A/dm ²

‧Time: Adjust according to plating thickness

In addition, there are unavoidable impurities in the actual plating. The plating thickness was measured by the above-described fluorescent X-ray film thickness meter.

<1. Surface roughness>

The surface of each titanium-copper foil obtained by the rolling process is subjected to degreasing and washing, and then a contact-type roughness meter (SE-3400) manufactured by Kosaka Research Institute Co., Ltd. based on JIS B0601-2001. The arithmetic mean roughness Ra in the direction parallel to the rolling direction of the surface is measured.

<2. Gloss measurement>

In particular, when a copper foil is produced by rolling, its surface state can be expressed not only by roughness (Ra or the like) but also by glossiness. As described above, the gloss is a value which varies depending on the amount of the oil groove, and there is a case where the gloss of the material having the same surface roughness is different, so the influence on the fixing effect must be considered. Therefore, after degreasing and pickling and purifying the surface of each titanium copper foil obtained by the rolling process, the gloss meter handheld gloss meter PG-based by JIS Z8741-1997 is used. 1. The gloss of the copper foil before surface treatment was determined by the incident angle of 60 degrees in the rolling direction.

<3. Solder Bond Strength Test>

The solder bond strength was measured in accordance with the procedure of the solder bond strength test described above. Pb lead-free solder (ESC M705, composition: Sn-3.0% by mass Ag-0.5% by mass Cu) manufactured by Senju Metal Industry Co., Ltd., and each sample foil after plating (Comparative Example 1 was not plated) and A pure copper foil (C1100, foil thickness: 0.035 mm) was joined and measured by a 180° peel test at a speed of 100 mm/min using a precision load measuring device (MODEL-1605NL) manufactured by Aiko Engineering Co., Ltd. Average bond strength. After solder bonding, the bonding strength was measured before and after heating, and the heating conditions were set to 85 ° C and heated for 100 hours. The bonding strength after heating was evaluated as ○ when the bonding strength after heating was less than 5% with respect to the bonding strength before heating, and was evaluated as × when it was 5% or more.

<4. Composite environmental test>

The degree of discoloration of each sample foil in a thermostatic chamber at a temperature of 85 ° C and a relative humidity of 85% was examined for 100 hours. When compared with the 0.1 μm Ni plating material (Comparative Example 2), the evaluation was ◎, and compared with the bare material (Comparative Example 1), the color change was evaluated as ○, and the color change was the same as that of the bare material (Comparative Example 1). When it was large (including Comparative Example 1), it was evaluated as ×. According to this test, when the result of high discoloration resistance is obtained, the amount of residue generated in the surface of the sample foil (the amount of intermetallic compound produced) is indirectly indicated.

<5. Etching linearity>

Each sample foil was etched using a 37% by mass, Baume 40° chlorinated second iron aqueous solution to form a linear circuit having a line width of 100 μm and a length of 150 mm. The observation circuit (observation length: 200 μm) was observed using a scanning electron microscope (manufactured by Hitachi, S-4700). When the difference between the maximum circuit width and the minimum circuit width was less than 4 μm, it was evaluated as ◎, and when it was 4 to 10 μm, it was evaluated as ○, and when it was more than 10 μm, it was evaluated as ×.

<6. Strength test (tensile strength)>

With respect to the sample foil after plating in Example 1, when the tensile strength in the direction parallel to the rolling direction was measured by the above-described measuring method using a tensile tester, it was 1415 MPa.

The results are shown in Table 1-2. As can be seen from Table 1-2, the Sn plating layer can ensure the strength and the discoloration resistance of the solder joint, and the linearity of the etching can be improved.

Since Comparative Example 1 was not plated, the adhesion to the solder was inferior, and discoloration occurred after the composite environment test.

Comparative Example 2 in which Ni plating was performed in a titanium copper foil was compared with a bare material of a titanium copper foil, and the bonding strength with the solder was improved, and the discoloration after the composite environmental test and the gas corrosion test was also small, and the etching property was deteriorated.

Since the Sn plating layer of Comparative Example 3 was too thin, the solder adhesion and the discoloration resistance before and after heating were inferior to those of the examples.

The base materials of Comparative Examples 4 and 5 were too glossy, and thus the solder adhesion before and after heating was lowered.

[Table 1-1]

Claims (16)

A titanium copper foil characterized in that the base material has a composition of 1.5 to 5.0% by mass of Ti and the balance is composed of copper and unavoidable impurities; the base material has a thickness of 0.018 to 0.1 mm and has a surface on the base material. The Sn plating layer was measured according to the following solder bond strength test procedure: a lead-free solder (Sn-3.0% by mass Ag-0.5% by mass Cu) was used to make a coated titanium copper foil and a pure copper foil (specified in JIS H3100-2012). The alloy No. C1100 and the foil thickness 0.02 mm to 0.05 mm were joined. The titanium copper foil was a rectangle having a width of 15 mm and a length of 200 mm. The pure copper foil was a rectangle having a width of 20 mm and a length of 200 mm, and an area of 30 mm × 15 mm in the central portion in the longitudinal direction. Lead-free solder (0.4±0.02 mm in diameter and 120±1 mm in length) was taken into the above area, and on the basis of this, bonding was performed at 245 ° C ± 5 ° C as the bonding temperature, and after bonding, by 180 at a speed of 100 mm/min. In the peeling test of °, the bonding strength was measured, and the average value of the load (N) in the 40 mm range from 30 mm to 70 mm of the peeling displacement was defined as the bonding strength, and the bonding strength in the solder bonding strength test was 0.5 N or more. The titanium copper foil according to claim 1, wherein the Sn plating layer has a thickness of 0.01 to 2.0 μm. The titanium copper foil according to claim 1 or 2, wherein the base material further contains a total amount of 0 to 1.0% by mass selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, One or more elements of P, Si, Cr, and Zr. The titanium copper foil according to the first or second aspect of the invention, wherein the tensile strength in a direction parallel to the rolling direction is 1100 MPa or more. The titanium copper foil according to claim 1 or 2, wherein the bonding strength is 20N or more. The titanium copper foil according to claim 1 or 2, wherein a reduction rate of the bond strength after heating at a temperature of 85 ° C for 100 hours is less than 5% with respect to the bond strength before heating. The titanium copper foil according to claim 1 or 2, wherein the titanium copper foil is used for etching. An electronic component comprising the titanium copper foil according to any one of claims 1 to 7. A bonded body, which is a bonded body of a titanium copper foil and a solder according to any one of claims 1 to 7, which has a surface on the surface of the coated copper foil. The joint where the solder is bonded. A method of joining a titanium-copper foil and a conductive member, comprising the steps of: subjecting a titanium copper foil according to any one of claims 1 to 7 to shape processing by etching; The shaped workpiece of the obtained titanium copper foil was joined to the conductive member by welding at a portion having the plating layer. An automatic focusing module comprising the titanium copper foil according to any one of claims 1 to 7 as a spring material. An auto-focusing camera module, comprising: a lens; and an elastic force of the lens at an initial position in the optical axis direction, such as the titanium according to any one of claims 1 to 7. a spring member having a copper foil as a material; and an electromagnetic driving mechanism that generates an electromagnetic force against the force of the spring member to drive the lens in the optical axis direction; wherein the electromagnetic driving mechanism is provided with a coil, the spring member having the The portion of the coating is joined to the coil by soldering. A method for producing a titanium copper foil, comprising: a step of preparing a base material having a composition of 1.5 to 5.0% by mass of Ti, the balance being composed of copper and unavoidable impurities, and having a thickness of 0.018 ~0.1 mm, surface glossiness is 100 to 200; and a step of forming a Sn plating layer having a thickness of 0.01 μm or more on the surface of the base material. The method for producing a titanium copper foil according to claim 13, wherein the Sn plating layer has a thickness of 0.01 to 2.0 μm. The method for producing a titanium copper foil according to claim 13 or claim 14, wherein the base material further contains a total amount of 0 to 1.0% by mass selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, and Mo. One or more elements of Ni, P, Si, Cr, and Zr. The method for producing a titanium copper foil according to claim 13 or claim 14, wherein the arithmetic mean roughness Ra of the surface of the base material having a surface gloss of 100 to 200 is 0.5 μm or less.